The overall goal of our research program is to elucidate endogenous and other mechanisms of protection against ischemia-reperfusion (IR) injury, and to exploit this knowledge to develop new therapies for IR disease conditions such as heart attack and stroke. Many cardioprotective strategies appear to converge on mitochondrial potassium channels as necessary and sufficient effectors of protective signaling. However, the identity and regulation of these channels remains controversial. Our published research to date, and exciting preliminary data contained herein, have directed our focus to a novel mitochondrial K+ channel that is required for protection and has not previously been implicated in protective signaling. Notably, absence of this channel appears to yield a metabolic phenotype. We have also identified a novel class of endogenous channel modulators. In this proposal, Aim 1 will characterize the channel and its role in cardioprotection, Aim 2 will investigate links between the channel and cardiac metabolism, and Aim 3 will study its regulation by endogenous signals. We will use a variety of state-of-the -art techniques, including patch-clamp of mitoplasts (isolated mitochondrial inner membranes), and Seahorse XF methodology to assess cardiomyocyte bioenergetics. This dual-PI proposal draws on the expertise of both investigators (Brookes - mitochondrial biology, metabolic screening, cardiac patho-physiology; Nehrke - ion channels, mouse genetics, mitochondrial physiology). Our productive track-record (8 original research articles and 3 reviews funded by this project in 3 years) imparts a high probability that the completion of these 3 aims will yield critical information about this channel, which is a novel potential drug target for cardioprotection.